Peptide nucleic  acid based guanidinium compounds

ABSTRACT

Disclosed herein are transmembrane transporter compounds containing guanidinium groups to enhance transport across biomembranes. Therapeutic and other biologically active moieties may be attached to the compounds. The transmembrane transporter compounds may include peptide nucleic acid monomer units.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 11/525,482, filed Sep. 21, 2006, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application U.S. Provisional Application No. 60/720,067, filed Sep. 23, 2005; all of which are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the fields of chemistry and medicine. More particularly, the present invention relates to guanidinium containing compounds that exhibit enhanced transmembrane transport of biologically active molecules.

2. Description of the Related Art

Protein transduction domains (PTD) are short cationic peptides that are capable of delivering molecules into mammalian cells. They include many diverse peptide sequences from many diverse sources. The phenomenon that peptide sequences can assist molecules across biological barriers is ubiquitous in biological systems. Such phenomenon can take place at different levels, including subcellular (e.g., nuclear membranes), cellular (e.g., cell membranes), and tissue levels (e.g., epithelial tissue). Sometimes the same peptide sequences can promote different translocation events at different biological levels.

SUMMARY OF THE INVENTION

One embodiment disclosed herein includes a compound having the formula:

wherein:

each u and each v are separately selected to be an integer from 0 to 10, with the proviso that at least one SPU unit is present between two BB units;

w is an integer of from 1 to 50;

each L is separately selected to be a linker moiety comprising a molecular fragment having a molecular weight less than about 1000 or L is absent;

each T is a terminal group separately selected from the group consisting of hydrogen, hydroxy, an amine group, a carboxylic group, a N-terminal peptide or group that forms an N-terminal peptide bond with BB or SPU, a C-terminal peptide or group that forms a C-terminal peptide bond with BB or SPU, a reporting moiety, a targeting moiety, and a therapeutic moiety, or each T may be separately absent;

each BB is separately selected to be a backbone moiety comprising an organic fragment having a molecular weight less than about 5000;

each SPU is separately selected to be a spacer-unit moiety selected from the group consisting of mono-substituted, poly-substituted or unsubstituted, straight or branched chain variants of the following residues: C₂₋₂₀ alkyl, C₂₋₂₀ heteroalkyl, C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₃-C₂₀ heteroalkenyl, C₃-C₂₄ heteroalkynyl, C₅₋₃₀ aryl, and C₅₋₃₀ heteroaryl;

each R is separately selected from the group consisting of H, an optionally substituted amino acid, optionally substituted C₃-C₈ aryl, optionally substituted C₂-C₈ heteroaryl, optionally substituted C₁-C₂₀ alkyl, optionally substituted C₂-C₂₀ alkenyl, optionally substituted C₂-C₂₀ alkynyl, optionally substituted C₂-C₈ spirocycloalkylene, optionally substituted C₂-C₈ heterocyclyl, optionally substituted pyrimidine, and optionally substituted purine, wherein the pyrimidine and purine are optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl;

each G is separately selected to be a guanidinium group covalently attached to a BB group and having the formula:

wherein the point of attachment of G to BB is through a nitrogen atom or through R² or each G is separately selected from the group consisting of:

each R¹, R², R³, and R⁴ are separately selected from the group consisting of hydrogen, optionally substituted C₁-C₁₂ alkyl, optionally substituted C₂-C₁₂ alkenyl, optionally substituted C₂-C₁₂ alkynyl, and pentamethylchroman-6-sulfonyl;

each R¹ is optionally bound to the R², R³, or R⁴ on the same guanidinium group to form a heterocyclic ring;

each R² is optionally bound to the R³ or R⁴ on the same guanidinium group to form a heterocyclic ring; and

each R³ is optionally bound to the R⁴ on the same guanidinium group to form a heterocyclic ring.

In some embodiments, each BB-G is separately selected from the group consisting of:

In some embodiments, SPU—R has the formula:

In some embodiments, each G is separately selected from the group consisting of:

In some embodiments, R¹, R², R³, and R⁴ are hydrogen. In some embodiments, each m, n, p, and q are independently integers from 0 to 1.

In some embodiments, L is a cleavable linker. In some embodiments, the cleavable linker comprises an ester group. In some embodiments, the cleavable linker comprises a disulfide group. In some embodiments, the cleavable linker comprises a first cleavable group and a second cleavable group, wherein when the first cleavable group is cleaved, the first cleavable group is converted to a nucleophilic moiety that is adapted to react with the second cleavable group. In some embodiments, the first group is an amide group and the second group is an ester group, and cleavage of the amide group yields a free amino group that reacts with the ester group. In some embodiments, the first group is a phosphate ester group and the second group is a carboxylate ester group, and cleavage of the phosphate ester group yields a free hydroxyl group that reacts with the carboxylate ester group.

In some embodiments, each L is separately selected from the group consisting of: an oligopeptide comprising 1 to 12 amino acid residues, an optionally substituted C₁-C₁₂ alkyl, an optionally substituted C₂-C₁₂ alkenyl, an optionally substituted C₂-C₁₂ alkynyl, and an optionally substituted C₃₋₁₂ cyclic alkyl, alkenyl, alkynyl, or aromatic moiety.

In some embodiments, each L is separately selected from the group consisting of: —C(═O)NH—, —C(═O)NHO—, —C(═O)NHNH—, —S(═O)(═O)NR′—, —P(═O)(—OR′)NR″—, —SS—, —CH₂NR′—, —CH₂NR′—, —CH₂C(═O)NR′—, —C(═O)O—, —C(═S)NR′—, —S(═O)(═O)CH₂—, —SOCH₂— and —OC(═O)NR′—, wherein each R′ and R″ are separately selected from the group consisting of hydrogen, optionally substituted C₁-C₁₂ alkyl, optionally substituted C₂-C₁₂ alkenyl, and optionally substituted C₂-C₁₂ alkynyl.

In some embodiments, L is absent.

In various embodiments, at least one T comprises a polypeptide, protein antigen, tumor antigen, tisane moiety, antimicrobial agent, metal ion, or cleavable linker, including cleavable linkers having an ester group or a disulfide group such as described above. In some embodiments, at least one T comprises a peptide nucleic acid.

In some embodiments, each R is separately selected from the group consisting of an optionally substituted pyrimidine and an optionally substituted purine, the pyrimidine and purine optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl. In some embodiments, each R is separately selected from the group consisting of uracil, thymine, cytosine, adenine, and guanine, the uracil, thymine, cytosine, adenine, and guanine optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl. In some embodiments, at least one R has the formula:

Another embodiment disclosed herein includes a compound as described above having the formula:

wherein each m, n, p, and q are independently integers from 0 to 6 and r is an integer from 1 to 10.

One embodiment includes a compound having the formula:

In some embodiments, at least one R has the formula:

One embodiment includes a compound having the formula:

Another embodiment disclosed herein includes a polymer, comprising at least two arginine subunits and at least two peptide nucleic acid subunits. In some embodiments, at least two arginine subunits are adjacent to each other. In other embodiments, no arginine subunits are adjacent to each other. In some embodiments, the peptide nucleic acid subunit has the formula:

wherein R is selected from the group consisting of an optionally substituted pyrimidine and an optionally substituted purine, wherein the pyrimidine and purine are optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl.

Another embodiment disclosed herein includes a polymer, comprising at least two arginine subunits and at least two spacer subunits. In some embodiments, at least two arginine subunits are adjacent to each other. In some embodiments, no arginine subunits are adjacent to each other. In some embodiments, the spacer subunit has the formula:

wherein R is selected from the group consisting of H, an optionally substituted amino acid, optionally substituted C₃-C₂₀ aryl, optionally substituted C₂-C₂₀ heteroaryl, optionally substituted C₁-C₂₀ alkyl, optionally substituted C₂-C₂₀ alkenyl, optionally substituted C₂-C₂₀ alkynyl, optionally substituted C₂-C₈ spirocycloalkylene, optionally substituted C₂-C₈ heterocyclyl, optionally substituted pyrimidine, and optionally substituted purine, wherein the pyrimidine and purine are optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl.

Another embodiment disclosed herein includes a method for enhancing transport of a biologically active moiety across a biological membrane, comprising contacting a biological membrane with a compound of claim 1, wherein at least one T comprises a biologically active moiety, whereby the contacting is effective to promote transport of the compound across the biological membrane at a rate that is greater than a trans-membrane transport rate of the biologically active moiety in non-conjugated form. In some embodiments, the biological membrane is a eukaryotic cell membrane. In some embodiments, the eukaryotic cells selected from the group consisting of mammalian cells, cancer cells, insect cells, plant cells, and yeast cells. In some embodiments, the biological membrane is an epithelial layer in a body. In some embodiments, the epithelial layer is selected from the group consisting of skin, mucosmembrane, and brain blood barriers. In some embodiments, the biological membrane is a prokaryotic cell membrane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a fluorescence micrograph of cells exposed to a peptide nucleic acid transporter molecule and a control fluorescence micrograph.

FIG. 2 depicts a fluorescence micrograph of skin tissue exposed to a peptide nucleic acid transporter molecule and a control fluorescence micrograph.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Peptide Nucleic Acid (PNA), a synthetic analogue of DNA and RNA in which the natural sugar-phosphate backbone has been replaced by N-(2-aminoethyl)glycine exhibits high thermal stability and stability to both nucleases and proteases. Thus, PNAs may be suitable as rugged backbones for therapeutic delivery. However, PNAs are not readily taken up by mammalian cells and have a tendency to aggregate when in water solution. Accordingly, in one embodiment, transmembrane transport of PNA and other backbone containing molecules are enhanced by the attachment of transport promoting moieties. Oligoarginine sequences generated by replacing non-arginine residues with arginine in the HIV Tat 47-57 segment have been demonstrated to be effective at assisting molecules to cross cellular membranes and mammalian skin tissues. Thus, in one embodiment, guanidinium and related moieties are attached to PNA or other backbones to promote transmembrane transport.

In some embodiments, a guanidinium containing transporter molecule is provided having one or more therapeutic moieties attached thereto. Thus, the transporter-therapeutic complex can be readily transported into a cell where the therapeutic moiety can have therapeutic effect. Any therapeutic moiety that can be covalently bound to the transporter molecules disclosed herein may be used. Non-limiting examples of some therapeutic moieties include: immunosuppressives, antibacterials, antifungals, antivirals, antiproliferatives, hormones, antiinflammatories, vitamins, analgesics, diagnostics and imaging contrast agents. Some specific examples include: conjugated glucocorticoids for treating inflammatory skin diseases, conjugated retinoids for treating acne, skin cancer and psoriasis, conjugated cytotoxic and immunosuppressive drugs for treating cancer and leukemia, conjugated antiinflammatory and antifungal agents, conjugated antihistamines, conjugated anagelsics, conjugated photochemotherapeutic agents, sunscreen, conjugated antibiotics for treating bacteria infections, conjugated anti-neoplastic agents for treating cancers, conjugated antiinflammatory agents, bronchodialators and immunosuppressive drugs for treating pulmonary conditions, conjugated neurotransmitters, and analgesics and CNS drugs that are capable of crossing the blood brain barrier.

In some embodiments, the therapeutic moiety is attached to the transporter molecule via a cleavable linker moiety. The cleavable linker moiety may be such that once the transporter-therapeutic complex is transported into a cell, the linker is cleaved, freeing the therapeutic moiety from the complex. Those of skill in the art will recognize many cleavable linkers suitable for this purpose. Non-limiting examples of cleavable linkers include moieties containing di-sulfide functionalities or acid-degradable functionalities such as esters. In some embodiments, a targeting moiety may also be attached to the multivalent arginine transporter molecule. The targeting moiety may be any moiety that preferentially binds to receptors on one or more cell types. Thus, a transporter-targeting-therapeutic complex is provided that preferentially is transported into one or more cell types where the therapeutic moiety can have therapeutic effect. Those of skill in the art will recognize many suitable targeting moieties. Non-limiting examples of some targeting moieties include: small molecules, oligo peptides, oligonucleotides, and macromolecules obtainable from synthetic or natural resources that have specific interactions with molecular targets implicated in the following diseases, including Acute lymphoblastic leukemia, Advanced pancreatic tumor, Affective disorder, AIDS, Allergic rhinitis, Allergy, Alzheimer's, Analgesic, Anesthesia, ANF degradation, Angiogenesis, Anxiety, Arthritis, Asthma, Autoimmune disease, Bacterial infection, Baldness, Blood coagulation, Bone Loss, Brain ischaemia, Breast cancer, Calcium deficiency, Carcinoid syndrome, Cardiac failure, Cardiovascular disease, Chronic myelogenous leukemia, Cognitive dysfunction, Colon cancer, Common cold, Common roundworm, Congestive heart failure, Cystic fibrosis, Dementia, Depression, Diabetes, Diabetic retinopathy, Diarrhea, Drug dependence, Erectile dysfunction, Fever, Fungal infection, Gastric tumor, Glaucoma, Gout, Heart disease, Heart failure, Helminth infection, Hepatitis C, Herpes, High blood glucose level, High blood sugar level, High cholesterol, Hirsutism, Hormone-dependent tumors, Human African trypanosomiasis, Hypertension, Hyperthyroidism, Hypocalcaemia, Immune response, Immunodeficiency, Inflammation, Influenza A and B, Insomnia, Irritable bowel syndrome, Kidney failure, Leukemia, Liposarcoma, Liver, Local anesthetic, Lung cancer, Lupus, Malaria, Malignant pain, Melanoma, Metastasis, Migraine, Morning sickness, Motion sickness, Motor disorder, Movement disorder, Nasal congestion, Neurodegeneration, Neuropathic, Obesity, Obstructive pulmonary disease, Ocular hypertension/glaucoma, Osteoporosis, Ovarian, Pain, Parkinson's, Peptic ulcer, Phaeochromocytoma, Platelet adhesion, Platelet disease, Posterior pituitary disorder, Postsurgical pain, Prostate adenocarcinoma, Prostate tumor, Prostatic hyperplasia, Psychiatric illness, Psychomotor, Reproduction diseases, Respiration diseases, Rheumatoid, Riboflavin deficiency, Schizophrenia, Seizure, Smoking addiction, Solid tumor, Thiamine deficiency, Tuberculosis, Urinary tract infection, Urticaria, Uterus contraction, Vascular disease, Viral infection, Visceral, Vitamin A deficiency, Vitamin B12 deficiency, Vitamin B6 deficiency, Vitamin C deficiency, Vitamin D deficiency, Vomiting, and Zollinger-Ellison syndrome.

In one embodiment, the transporter molecules for use as described herein have the structure:

BB represents a back-bone moiety to which guanidinium moieties G may be attached. SPU represents a spacer-unit moiety to provide molecular spacers between multiple BB-G units. In some embodiments, SPU—R may include PNA moieties. Thus, the SPU—R units together with the BB units may provide a backbone structure that includes PNA units and attached guanidinium moieties G. Accordingly, a rugged PNA containing molecule may be provided that also has transmembrane functionality due to attached guanidinium moieties. Because a given molecule may have multiple SPU and/or BB units, each separate SPU and BB unit may be selected separately. Thus, some or all of the SPU units may be different from other SPU units and some or all of the BB units may be different from other BB units.

Each u and each v may be separately selected to be an integer from 0 to 10. Thus, each repeated unit w may contain multiple SPU and BB units or optionally may contain no SPU unit or no BB unit. Accordingly, in some cases, the transporter molecule may include domains of multiple BB units bound together in a chain with no intervening SPU unit. Similarly, the transporter molecule may contain domains of multiple SPU units bound together in a chain with no intervening BB units. w may be an integer of from 1 to 50. As noted above, each SPU—R unit and each BB-G unit, whether within the same w unit or different w units may be different from other SPU—R and BB-G units in the molecule.

BB is a backbone moiety comprising an organic fragment that provides a scaffold upon which guanidinium moieties G may be attached. In one simple example, BB-G is an arginine residue. In one embodiment, BB is an organic fragment having a molecular weight less than about 10,000. In one embodiment, BB is an organic fragment having a molecular weight less than about 5,000. In one embodiment, BB is an organic fragment having a molecular weight less than about 1,000.

Some non-limiting examples of backbone moieties BB with attached guanidinium groups G include:

G represents a guanidinium moiety and may have the structure:

where the point of attachment of G to BB is through the nitrogen atom or through R² or, alternatively, each G may be selected from the group consisting of:

Each R¹, R², R³, and R⁴ may be separately selected from the group consisting of hydrogen, optionally substituted C₁-C₁₂ alkyl, optionally substituted C₂-C₁₂ alkenyl, optionally substituted C₂-C₁₂ alkynyl, and an N protecting group such as pentamethylchroman-6-sulfonyl. The wavy line indicates where guanidinium moiety G attaches to a backbone moiety BB. R¹, R², R³, and R⁴ on each guanidinium moiety G may be the same or different from R¹, R², R³, and R⁴ groups on other guanidinium moieties G. In some embodiments, R¹ may be optionally bound to a R², R³, or R⁴ group on the same guanidinium group to form a heterocyclic ring within the guanidinium group. Similarly, in some embodiments, R² may be optionally bound to a R³ or R⁴ group on the same guanidinium group to form a heterocyclic ring or R³ may be optionally bound to the R⁴ on the same guanidinium group to form a heterocyclic ring.

Some non-limiting examples of G include:

Each SPU is a spacer unit separately selected from the group consisting of mono-substituted, poly-substituted or unsubstituted, straight or branched chain variants of the following residues: C₂₋₂₀ alkyl, C₂₋₂₀ heteroalkyl, C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₃-C₂₀ heteroalkenyl, C₃-C₂₄ heteroalkynyl, C₅₋₃₀ aryl, and C₅₋₃₀ heteroaryl. In a non-limiting example, an SPU—R has the structure of:

where the wavy lines indicate the attachment points of SPU to the rest of the molecule.

Each R bound to an SPU unit may be separately selected from the group consisting of H, optionally substituted amino acid, optionally substituted C₃-C₈ aryl, optionally substituted C₂-C₈ heteroaryl, optionally substituted C₁-C₂₀ alkyl, optionally substituted C₂-C₂₀ alkenyl, optionally substituted C₂-C₂₀ alkynyl, optionally substituted C₂-C₈ spirocycloalkylene, optionally substituted C₂-C₈ heterocyclyl, optionally substituted pyrimidine, and optionally substituted purine. When pyrimidine and purine moieties are present, they may be optionally linked to the SPU unit via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl. In some embodiments, each R is separately selected from the group consisting of uracil, thymine, cytosine, adenine, and guanine. The uracil, thymine, cytosine, adenine, and guanine may optionally be linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl. Some non-limiting examples of R include:

where the wavy line indicates the point of attachment of R to the SPU unit.

L is a linker moiety comprising a molecular fragment that links T to the rest of the molecule. Each separate linker moiety L may be the same or different from other linker moieties L. As discussed above, linker moiety L may optionally be a cleavable linker designed to cleave a terminal group T from the transporter molecule under certain conditions. The cleavable linker may include an ester group that can by hydrolyzed by an enzyme within a subject. Alternatively, the cleavable linker may include a disulfide group that can also be enzymatically cleaved. In some embodiments, the cleavable linker may include two cleavable groups such that when one cleavable group is cleaved, it is converted to a nucleophilic moiety that reacts with the other cleavable group. In one embodiment, the first cleavable group is an amide group and the second group is an ester group so that cleavage of the amide group yields a free amino group that reacts with the ester group. In another embodiment, the first cleavable group is a phosphate ester group and the second group is a carboxylate ester group so that cleavage of the phosphate ester group yields a free hydroxyl group that reacts with the carboxylate ester group. In some embodiments, L is a molecular fragment having a molecular weight less than about 5000. In some embodiments, L is a molecular fragment having a molecular weight less than bout 1000. In some embodiments, L is a molecular fragment having a molecular weight less than about 500.

T represents terminal groups attached to each end of the molecule. Terminal group T may serve the function of merely terminating the chain or may also include therapeutic, targeting, or reporting moieties. When a terminal group T includes a therapeutic moiety, the moiety may be linked to the rest of the molecule through a cleavable linker such as described above. Each T group may be the same or different from the other T group. In some embodiments, each terminal group T may be separately selected from the group consisting of hydrogen, hydroxy, an amine group, a carboxylic group, an N-terminal peptide or group that forms an N-terminal peptide bond with BB or SPU, a C-terminal peptide or group that forms a C-terminal peptide bond with BB or SPU, a reporting moiety, a therapeutic moiety, and a targeting moiety. Alternatively, a T group may be absent if a terminal BB group does not require a terminating group, such as when a guanidinium moiety G terminates the backbone chain.

Non-limiting examples of T include a polypeptide, a protein antigen, a tumor antigen, a tisane moiety, a metal ion, or an antimicrobial agent.

In some embodiments, the compound described above has the formula:

Each m, n, p, and q may be separately selected to be integers from 0 to 6. Accordingly, in some cases, the transporter molecule may include domains of multiple G containing moieties bound together in a chain with no intervening R containing moieties. Similarly, the transporter molecule may contain domains of multiple R containing moieties bound together in a chain with no intervening G containing moieties. r may be an integer from 1 to 10. Each G and each R, whether within the same r unit or different r units may be different from other G and R groups in the molecule. G and R are as described above. In one embodiment, each m, n, p, and q are separately integers from 0 to 1.

Some non-limiting examples of transporter molecules for use as described herein include the following molecules:

Some embodiments include a polymer that has at least two arginine subunits and at least two peptide nucleic acid subunits. In one embodiment, at least two arginine subunits are adjacent to each other. In another embodiment, no arginine subunits are adjacent to each other. In some embodiments, the peptide nucleic acid subunit has the formula:

where R is selected from the group consisting of an optionally substituted pyrimidine and an optionally substituted purine, wherein the pyrimidine and purine are optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl.

Other embodiments include a polymer having at least two arginine subunits and at least two spacer subunits. In some embodiments, the spacer unit has the

where R is selected from the group consisting of H, an optionally substituted amino acid, optionally substituted C₃-C₂₀ aryl, optionally substituted C₂-C₂₀ heteroaryl, optionally substituted C₁-C₂₀ alkyl, optionally substituted C₂-C₂₀ alkenyl, optionally substituted C₂-C₂₀ alkynyl, optionally substituted C₂-C₈ spirocycloalkylene, optionally substituted C₂-C₈ heterocyclyl, optionally substituted pyrimidine, and optionally substituted purine, wherein the pyrimidine and purine are optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl, optionally substituted C₂-C₈ alkenyl, or optionally substituted C₂-C₈ alkynyl.

Where the compounds disclosed herein have at least one chiral center, they may exist as a racemate or as enantiomers. It should be noted that all such isomers and mixtures thereof are included in the scope of the present invention. Furthermore, some of the crystalline forms for the compounds of disclosed herein may exist as polymorphs. Such polymorphs are included in one embodiment of the present invention. In addition, some of the compounds of the present invention may form solvates with water (i.e., hydrates) or common organic solvents. Such solvates are included in one embodiment of the present invention.

In some embodiments, the compounds disclosed herein may be provided in a pharmaceutically acceptable salt. The term “pharmaceutically acceptable salt” refers to a salt of a compound that does not cause significant irritation to an organism to which it is administered and does not abrogate the biological activity and properties of the compound. In some embodiments, the salt is an acid addition salt of the compound. Pharmaceutical salts can be obtained by reacting a compound with inorganic acids such as hydrohalic acid (e.g., hydrochloric acid or hydrobromic acid), sulfuric acid, nitric acid, phosphoric acid and the like. Pharmaceutical salts can also be obtained by reacting a compound with an organic acid such as aliphatic or aromatic carboxylic or sulfonic acids, for example acetic, succinic, lactic, malic, tartaric, citric, ascorbic, nicotinic, methanesulfonic, ethanesulfonic, p-toluensulfonic, salicylic or naphthalenesulfonic acid. Pharmaceutical salts can also be obtained by reacting a compound with a base to form a salt such as an ammonium salt, an alkali metal salt, such as a sodium or a potassium salt, an alkaline earth metal salt, such as a calcium or a magnesium salt, a salt of organic bases such as dicyclohexylamine, N-methyl-D-glucamine, tris(hydroxymethyl)methylamine, C₁-C₇ alkylamine, cyclohexylamine, triethanolamine, ethylenediamine, and salts with amino acids such as arginine, lysine, and the like.

If the manufacture of pharmaceutical formulations involves intimate mixing of the pharmaceutical excipients and the active ingredient in its salt form, then it may be desirable to use pharmaceutical excipients which are non-basic, that is, either acidic or neutral excipients.

In various embodiments, the compounds disclosed herein can be used alone, in combination with other compounds disclosed herein, or in combination with one or more other agents that are therapeutically active.

The term “halogen atom,” as used herein, means any one of the radio-stable atoms of column 7 of the Periodic Table of the Elements, e.g., fluorine, chlorine, bromine, or iodine, with fluorine and chlorine being preferred.

The term “ester” refers to a chemical moiety with formula —(R)_(n)—COOR′, where R and R′ are independently selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl (bonded through a ring carbon) and heteroalicyclic (bonded through a ring carbon), and where n is 0 or 1.

An “amide” is a chemical moiety with formula —(R)_(n)—C(O)NHR′ or —(R)_(n)—NHC(O)R′, where R and R′ are independently selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl (bonded through a ring carbon) and heteroalicyclic (bonded through a ring carbon), and where n is 0 or 1. An amide may be an amino acid or a peptide molecule attached to a molecule of the present invention, thereby forming a prodrug.

Any amine, hydroxy, or carboxyl side chain on the compounds of the present invention can be esterified or amidified. The procedures and specific groups to be used to achieve this end are known to those of skill in the art and can readily be found in reference sources such as Greene and Wuts, Protective Groups in Organic Synthesis, 3^(rd) Ed., John Wiley & Sons, New York, N.Y., 1999, which is incorporated herein in its entirety.

The term “aromatic” refers to an aromatic group which has at least one ring having a conjugated pi electron system and includes both carbocyclic aryl (e.g., phenyl) and heterocyclic aryl groups (e.g., pyridine). The term includes monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups. The term “carbocyclic” refers to a compound which contains one or more covalently closed ring structures, and that the atoms forming the backbone of the ring are all carbon atoms. The term thus distinguishes carbocyclic from heterocyclic rings in which the ring backbone contains at least one atom which is different from carbon. The term “heteroaromatic” refers to an aromatic group which contains at least one heterocyclic ring.

The term “alkyl,” as used herein, means any unbranched or branched, substituted or unsubstituted, saturated hydrocarbon. The alkyl moiety, may be branched, straight chain, or cyclic. The alkyl group may have 1 to 20 carbon atoms (whenever it appears herein, a numerical range such as “1 to 20” refers to each integer in the given range; e.g., “1 to 20 carbon atoms” means that the alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 20 carbon atoms, although the present definition also covers the occurrence of the term “alkyl” where no numerical range is designated). The alkyl group may also be a medium size alkyl having 1 to 10 carbon atoms. The alkyl group could also be a lower alkyl having 1 to 5 carbon atoms. The alkyl group may be designated as “C₁-C₄ alkyl” or similar designations. By way of example only, “C₁-C₄ alkyl” indicates that there are one to four carbon atoms in the alkyl chain, i.e., the alkyl chain is selected from the group consisting of methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and t-butyl.

The alkyl group may be substituted or unsubstituted. When substituted, the substituent group(s) is(are) one or more group(s) individually and independently selected from substituted or unsubstituted cycloalkyl, substituted or unsubstituted cylcloalkenyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaryloxy, heterocyclyl, heterocyclooxy, heteroalicyclyl, hydroxy, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, acyl, thiol, substituted or unsubstituted thioalkoxy, alkylthio, arylthio, cyano, halo, carbonyl, thiocarbonyl, acylalkyl, acylamino, acyloxy, aminoacyl, aminoacyloxy, oxyacylamino, keto, thioketo, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, trihalomethanesulfonyl, and substituted or unsubstituted amino, including mono-and di-substituted amino groups, and the protected derivatives thereof, hydroxyamino, alkoxyamino, nitro, —SO-alkyl, —SO-substituted alkyl, —SO-aryl, —SO-heteroaryl, —SO₂-alkyl, —SO₂-substituted alkyl, —SO₂-aryl and —SO₂-heteroaryl. Typical alkyl groups include, but are in no way limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, hexyl, ethenyl, propenyl, butenyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. Wherever a substituent is described as being “optionally substituted” that substituent may be substituted with one of the above substituents.

In the present context, the term “cycloalkyl” is intended to cover three-, four-, five-, six-, seven-, and eight-or more membered rings comprising carbon atoms only. A cycloalkyl can optionally contain one or more unsaturated bonds situated in such a way, however, that an aromatic pi-electron system does not arise. Some examples of “cycloalkyl” are the carbocycles cyclopropane, cyclobutane, cyclopentane, cyclopentene, cyclopentadiene, cyclohexane, cyclohexene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, cycloheptane, or cycloheptene.

An “alkenyl” moiety refers to a group consisting of at least two carbon atoms and at least one carbon-carbon double bond. An alkenyl may be unbranched or branched, substituted or unsubstituted, unsaturated hydrocarbon including polyunsaturated hydrocarbons. In some embodiments, the alkenyl is a C₁-C₆ unbranched, mono-unsaturated or di-unsaturated, unsubstituted hydrocarbons. The term “cycloalkenyl” refers to any non-aromatic hydrocarbon ring, preferably having five to twelve atoms comprising the ring.

An “alkyne” moiety refers to a group consisting of at least two carbon atoms and at least one carbon-carbon triple bond.

Unless otherwise indicated, the substituent “R” appearing by itself and without a number designation refers to a substituent selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl (bonded through a ring carbon) and heteroalicyclyl (bonded through a ring carbon).

The term “alkoxy” refers to any unbranched, or branched, substituted or unsubstituted, saturated or unsaturated ether, with C₁-C₆ unbranched, saturated, unsubstituted ethers being preferred, with methoxy being preferred, and also with dimethyl, diethyl, methyl-isobutyl, and methyl-tert-butyl ethers also being preferred. The term “cycloalkoxy” refers to any non-aromatic hydrocarbon ring, preferably having five to twelve atoms comprising the ring.

An “O-carboxy” group refers to a RC(═O)O— group, where R is as defined herein.

A “C-carboxy” group refers to a —C(═O)OR groups where R is as defined herein.

An “acetyl” group refers to a —C(═O)CH₃, group.

A “trihalomethanesulfonyl” group refers to a X₃CS(═O)₂— group where X is a halogen.

A “cyano” group refers to a —CN group.

An “isocyanato” group refers to a —NCO group.

A “thiocyanato” group refers to a —CNS group.

An “isothiocyanato” group refers to a —NCS group.

A “sulfinyl” group refers to a —S(═O)—R group, with R as defined herein.

A “S-sulfonamido” group refers to a —S(═O)₂NR, group, with R as defined herein.

A “N-sulfonamido” group refers to a RS(═O)₂NH— group with R as defined herein.

A “trihalomethanesulfonamido” group refers to a X₃CS(═O)₂NR— group with X and R as defined herein.

An “O-carbamyl” group refers to a —OC(═O)—NR, group-with R as defined herein.

An “N-carbamyl” group refers to a ROC(═O)NH— group, with R as defined herein.

An “O-thiocarbamyl” group refers to a —OC(═S)—NR, group with R as defined herein.

An “N-thiocarbamyl” group refers to an ROC(═S)NH— group, with R as defined herein.

A “C-amido” group refers to a —C(═O)—NR₂ group with R as defined herein.

An “N-amido” group refers to a RC(═O)NH— group, with R as defined herein.

The term “perhaloalkyl” refers to an alkyl group where all of the hydrogen atoms are replaced by halogen atoms.

The term “acylalkyl” refers to a RC(═O)R′— group, with R as defined herein, and R′ being a diradical alkylene group. Examples of acylalkyl, without limitation, may include CH₃C(═O)CH₂—, CH₃C(═O)CH₂CH₂—, CH₃CH₂C(═O)CH₂CH₂—, CH₃C(═O)CH₂CH₂CH₂—, and the like.

Unless otherwise indicated, when a substituent is deemed to be “optionally substituted,” it is meant that the substituent is a group that may be substituted with one or more group(s) individually and independently selected from cycloalkyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, cyano, halo, carbonyl, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, trihalomethanesulfonyl, and amino, including mono-and di-substituted amino groups, and the protected derivatives thereof. The protecting groups that may form the protective derivatives of the above substituents are known to those of skill in the art and may be found in references such as Greene and Wuts, above.

The term “heterocyclyl” is intended to mean three-, four-, five-, six-, seven-, and eight-or more membered rings wherein carbon atoms together with from 1 to 3 heteroatoms constitute the ring. A heterocyclyl can optionally contain one or more unsaturated bonds situated in such a way, however, that an aromatic pi-electron system does not arise. The heteroatoms are independently selected from oxygen, sulfur, and nitrogen.

A heterocyclyl can further contain one or more carbonyl or thiocarbonyl functionalities, so as to make the definition include oxo-systems and thio-systems such as lactams, lactones, cyclic imides, cyclic thioimides, cyclic carbamates, and the like.

Heterocyclyl rings can optionally also be fused to aryl rings, such that the definition includes bicyclic structures. Typically such fused heterocyclyl groups share one bond with an optionally substituted benzene ring. Examples of benzo-fused heterocyclyl groups include, but are not limited to, benzimidazolidinone, tetrahydroquinoline, and methylenedioxybenzene ring structures.

Some examples of “heterocyclyls” include, but are not limited to, tetrahydrothiopyran, 4H-pyran, tetrahydropyran, piperidine, 1,3-dioxin, 1,3-dioxane, 1,4-dioxin, 1,4-dioxane, piperazine, 1,3-oxathiane, 1,4-oxathiin, 1,4-oxathiane, tetrahydro-1,4-thiazine, 2H-1,2-oxazine, maleimide, succinimide, barbituric acid, thiobarbituric acid, dioxopiperazine, hydantoin, dihydrouracil, morpholine, trioxane, hexahydro-1,3,5-triazine, tetrahydrothiophene, tetrahydrofuran, pyrroline, pyrrolidine, pyrrolidone, pyrrolidione, pyrazoline, pyrazolidine, imidazoline, imidazolidine, 1,3-dioxole, 1,3-dioxolane, 1,3-dithiole, 1,3-dithiolane, isoxazoline, isoxazolidine, oxazoline, oxazolidine, oxazolidinone, thiazoline, thiazolidine, and 1,3-oxathiolane. Binding to the heterocycle can be at the position of a heteroatom or via a carbon atom of the heterocycle, or, for benzo-fused derivatives, via a carbon of the benzenoid ring.

In the present context the term “aryl” is intended to mean a carbocyclic aromatic ring or ring system. Moreover, the term “aryl” includes fused ring systems wherein at least two aryl rings, or at least one aryl and at least one C₃₋₈-cycloalkyl share at least one chemical bond. Some examples of “aryl” rings include optionally substituted phenyl, naphthalenyl, phenanthrenyl, anthracenyl, tetralinyl, fluorenyl, indenyl, and indanyl. The term “aryl” relates to aromatic, including, for example, benzenoid groups, connected via one of the ring-forming carbon atoms, and optionally carrying one or more substituents selected from heterocyclyl, heteroaryl, halo, hydroxy, amino, cyano, nitro, alkylamido, acyl, C₁₋₆ alkoxy, C₁₋₆ alkyl, C₁₋₆ hydroxyalkyl, C₁₋₆ aminoalkyl, C₁₋₆ alkylamino, alkylsulfenyl, alkylsulfinyl, alkylsulfonyl, sulfamoyl, or trifluoromethyl. The aryl group can be substituted at the para and/or meta positions. In other embodiments, the aryl group can be substituted at the ortho position. Representative examples of aryl groups include, but are not limited to, phenyl, 3-halophenyl, 4-halophenyl, 3-hydroxyphenyl, 4-hydroxyphenyl, 3-aminophenyl, 4-aminophenyl, 3-methylphenyl, 4-methylphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 4-trifluoromethoxyphenyl 3-cyanophenyl, 4-cyanophenyl, dimethylphenyl, naphthyl, hydroxynaphthyl, hydroxymethylphenyl, trifluoromethylphenyl, alkoxyphenyl, 4-morpholin-4-ylphenyl, 4-pyrrolidin-1-ylphenyl, 4-pyrazolylphenyl, 4-triazolylphenyl, and 4-(2-oxopyrrolidin-1-yl)phenyl.

In the present context, the term “heteroaryl” is intended to mean a heterocyclic aromatic group where one or more carbon atoms in an aromatic ring have been replaced with one or more heteroatoms selected from the group comprising nitrogen, sulfur, phosphorous, and oxygen.

Furthermore, in the present context, the term “heteroaryl” comprises fused ring systems wherein at least one aryl ring and at least one heteroaryl ring, at least two heteroaryl rings, at least one heteroaryl ring and at least one heterocyclyl ring, or at least one heteroaryl ring and at least one cycloalkyl ring share at least one chemical bond.

The term “heteroaryl” is understood to relate to aromatic, C₃₋₈ cyclic groups further containing one oxygen or sulfur atom or up to four nitrogen atoms, or a combination of one oxygen or sulfur atom with up to two nitrogen atoms, and their substituted as well as benzo-and pyrido-fused derivatives, for example, connected via one of the ring-forming carbon atoms. Heteroaryl groups can carry one or more substituents, selected from halo, hydroxy, amino, cyano, nitro, alkylamido, acyl, C₁₋₆-alkoxy, C₁₋₆-alkyl, C₁₋₆-hydroxyalkyl, C₁₋₆-aminoalkyl, C₁₋₆-alkylamino, alkylsulfenyl, alkylsulfinyl, alkylsulfonyl, sulfamoyl, or trifluoromethyl. In some embodiments, heteroaryl groups can be five-and six-membered aromatic heterocyclic systems carrying 0, 1, or 2 substituents, which can be the same as or different from one another, selected from the list above. Representative examples of heteroaryl groups include, but are not limited to, unsubstituted and mono-or di-substituted derivatives of furan, benzofuran, thiophene, benzothiophene, pyrrole, pyridine, indole, oxazole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole, isothiazole, imidazole, benzimidazole, pyrazole, indazole, tetrazole, quionoline, isoquinoline, pyridazine, pyrimidine, purine and pyrazine, furazan, 1,2,3-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, triazole, benzotriazole, pteridine, phenoxazole, oxadiazole, benzopyrazole, quinolizine, cinnoline, phthalazine, quinazoline, and quinoxaline. In some embodiments, the substituents are halo, hydroxy, cyano, O—C₁₋₆-alkyl, C₁₋₆-alkyl, hydroxy-C₁₋₆-alkyl, and amino-C₁₋₆-alkyl.

As used herein, the term “guanidinium group” refers to a moiety having the formula:

where R¹, R², R³, and R⁴ are as described above and the wavy line represent the point of attachment of the group to the rest of a molecule. Methods of Preparation

The compounds disclosed herein may be synthesized by methods described below, or by modification of these methods. Ways of modifying the methodology include, among others, temperature, solvent, reagents etc., and will be obvious to those skilled in the art. In general, during any of the processes for preparation of the compounds disclosed herein, it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry (ed. J. F. W. McOmie, Plenum Press, 1973); and Greene & Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 1991, which are both hereby incorporated herein by reference in their entirety. The protecting groups may be removed at a convenient subsequent stage using methods known from the art. Synthetic chemistry transformations useful in synthesizing applicable compounds are known in the art and include e.g. those described in R. Larock, Comprehensive Organic Transformations, VCH Publishers, 1989, or L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons, 1995, which are both hereby incorporated herein by reference in their entirety.

The transporter molecules described herein may be prepared by linking together guanidinium group containing monomers and spacer unit monomers. Spacer unit monomers may be synthesized by techniques known in the art. In some embodiments, spacer unit monomers containing amine and carboxylic terminal groups may be synthesized using techniques known in the art. For example, N-(2-aminoethyl)glycine and related spacer unit monomers may be synthesized by coupling of a diamine compound with a halogenated t-butyl ester as described further in Stephen A. Thomson, et al, Tetrahedron Vol. 51, No. 22, pp. 6179-6194, 1995, which is incorporated herein by reference in its entirety. The t-butyl group may then be removed by treatment with an acid. In some embodiments, the 2-amino group may be functionalized, such as with a purine or pyrimidine group, by first protecting the terminal amine group, such as with Fmoc, and then reacting with the carboxylic functionalized purine or pyrimidine group, as described further in Stephen A. Thomson, et al, Tetrahedron Vol. 51, No. 22, pp. 6179-6194, 1995.

The guanidinium group containing monomers may be synthesized by techniques known in the art. In some embodiments, the guanidinium group containing monomers are arginine residues or derivatives thereof.

Formation of polymers containing the guanidinium and spacer unit monomers may be obtained by using commercially available solid phase techniques. For example, the polymer may be grown on a Rink Amide MBHA resin. Fmoc protected guanidinium containing peptides may be coupled in the presence of PyBOP/DIPEA/DMAP and subsequently deprotected by treatment with Ac₂O/DIPEA/DMF and 20% Piperidine/DMF. Fmoc protected spacer unit monomers, such as peptide nucleic acid monomers, may be similarly coupled in the presence of PyBOP/DIPEA/DMAP. These coupling steps may be repeated in any desired order to obtain the desired polymer.

Although the polymer linkages in the method described above involve formation of peptide bonds, those of skill in the art will recognize other functional groups that could be used to form linkages between the monomer units of the molecule, such as by forming ester bonds between the monomers.

Where the processes for the preparation of the compounds disclosed herein give rise to mixtures of stereoisomers, such isomers may be separated by conventional techniques such as preparative chiral chromatography. The compounds may be prepared in racemic form or individual enantiomers may be prepared by stereoselective synthesis or by resolution. The compounds may be resolved into their component enantiomers by standard techniques, such as the formation of diastereomeric pairs by salt formation with an optically active acid, such as (−)-di-p-toluoyl-d-tartaric acid and/or (+)-di-p-toluoyl-1-tartaric acid, followed by fractional crystallization and regeneration of the free base. The compounds may also be resolved using a chiral auxiliary by formation of diastereomeric derivatives such as esters, amides or ketals followed by chromatographic separation and removal of the chiral auxiliary.

Methods of Use

In some embodiments, the transporter molecules described above may be used to enhance transport of a drug across a cell membrane. In one embodiment, enhancing transport of a drug across a cell membrane comprises linking a therapeutic moiety to the transporter molecule. The therapeutic moiety may be any suitable radical of a therapeutically effective drug. In some embodiments, the therapeutic moiety is linked to the transporter molecule via a cleavable linker such that when the molecule is within a cell, the therapeutic moiety is cleaved, generating the drug molecule. In some embodiments, a targeting moiety is also attached to the transporter molecule. The targeting moiety may be a moiety that preferentially binds to receptors on one or more cell types. Thus, the transporter molecule will have increased affinity to particular cell types, and thus increased transport across the membrane of those cell types. In this way, a drug can be effectively delivered specifically to the interior of cells where the drug will have its most beneficial effect.

In some embodiments, the cell membrane across which the transporter molecule passes is a eukaryotic cell membrane, such as the membrane in mammalian cells, cancer cells, insect cells, plant cells, or yeast cells. In other embodiments, the membrane is a prokaryotic cell membrane, such as bacteria cell membrane.

In some embodiments, a method is provided for converting a drug to a form that is more bioavailable. The method may comprise linking the drug to a transporter molecule as described herein. The transporter molecule will exhibit enhanced transport across cellular membranes and thus the attached drug will be more bioavailable than when delivered alone.

In some embodiments, the transporter molecules described herein may similarly be used to enhance transport of a drug across epithelial tissue, such as across skin, mucosmembrane, and brain blood barriers.

Pharmaceutical Compositions

In another aspect, the present disclosure relates to a pharmaceutical composition comprising physiologically acceptable surface active agents, carriers, diluents, excipients, smoothing agents, suspension agents, film forming substances, and coating assistants, or a combination thereof; and a compound disclosed herein. Acceptable carriers or diluents for therapeutic use are well known in the pharmaceutical art, and are described, for example, in Remington's Pharmaceutical Sciences, 18th Ed., Mack Publishing Co., Easton, Pa. (1990), which is incorporated herein by reference in its entirety. Preservatives, stabilizers, dyes, sweeteners, fragrances, flavoring agents, and the like may be provided in the pharmaceutical composition. For example, sodium benzoate, ascorbic acid and esters of p-hydroxybenzoic acid may be added as preservatives. In addition, antioxidants and suspending agents may be used. In various embodiments, alcohols, esters, sulfated aliphatic alcohols, and the like may be used as surface active agents; sucrose, glucose, lactose, starch, crystallized cellulose, mannitol, light anhydrous silicate, magnesium aluminate, magnesium methasilicate aluminate, synthetic aluminum silicate, calcium carbonate, sodium acid carbonate, calcium hydrogen phosphate, calcium carboxymethyl cellulose, and the like may be used as excipients; magnesium stearate, talc, hardened oil and the like may be used as smoothing agents; coconut oil, olive oil, sesame oil, peanut oil, soya may be used as suspension agents or lubricants; cellulose acetate phthalate as a derivative of a carbohydrate such as cellulose or sugar, or methylacetate-methacrylate copolymer as a derivative of polyvinyl may be used as suspension agents; and plasticizers such as ester phthalates and the like may be used as suspension agents.

The term “pharmaceutical composition” refers to a mixture of a compound disclosed herein with other chemical components, such as diluents or carriers. The pharmaceutical composition facilitates administration of the compound to an organism. Multiple techniques of administering a compound exist in the art including, but not limited to, oral, injection, aerosol, parenteral, and topical administration. Pharmaceutical compositions can also be obtained by reacting compounds with inorganic or organic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and the like.

The term “carrier” defines a chemical compound that facilitates the incorporation of a compound into cells or tissues. For example dimethyl sulfoxide (DMSO) is a commonly utilized carrier as it facilitates the uptake of many organic compounds into the cells or tissues of an organism.

The term “diluent” defines chemical compounds diluted in water that will dissolve the compound of interest as well as stabilize the biologically active form of the compound. Salts dissolved in buffered solutions are utilized as diluents in the art. One commonly used buffered solution is phosphate buffered saline because it mimics the salt conditions of human blood. Since buffer salts can control the pH of a solution at low concentrations, a buffered diluent rarely modifies the biological activity of a compound.

The term “physiologically acceptable” defines a carrier or diluent that does not abrogate the biological activity and properties of the compound.

The pharmaceutical compositions described herein can be administered to a human patient per se, or in pharmaceutical compositions where they are mixed with other active ingredients, as in combination therapy, or suitable carriers or excipient(s). Techniques for formulation and administration of the compounds of the instant application may be found in “Remington's Pharmaceutical Sciences,” Mack Publishing Co., Easton, Pa., 18th edition, 1990.

Suitable routes of administration may, for example, include oral, rectal, transmucosal, topical, or intestinal administration; parenteral delivery, including intramuscular, subcutaneous, intravenous, intramedullary injections, as well as intrathecal, direct intraventricular, intraperitoneal, intranasal, or intraocular injections. The compounds can also be administered in sustained or controlled release dosage forms, including depot injections, osmotic pumps, pills, transdermal (including electrotransport) patches, and the like, for prolonged and/or timed, pulsed administration at a predetermined rate.

The pharmaceutical compositions of the present invention may be manufactured in a manner that is itself known, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or tabletting processes.

Pharmaceutical compositions for use in accordance with the present invention thus may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen. Any of the well-known techniques, carriers, and excipients may be used as suitable and as understood in the art; e.g., in Remington's Pharmaceutical Sciences, above.

Injectables can be prepared in conventional forms, either as liquid solutions or suspensions, solid forms suitable for solution or suspension in liquid prior to injection, or as emulsions. Suitable excipients are, for example, water, saline, dextrose, mannitol, lactose, lecithin, albumin, sodium glutamate, cysteine hydrochloride, and the like. In addition, if desired, the injectable pharmaceutical compositions may contain minor amounts of nontoxic auxiliary substances, such as wetting agents, pH buffering agents, and the like. Physiologically compatible buffers include, but are not limited to, Hanks's solution, Ringer's solution, or physiological saline buffer. If desired, absorption enhancing preparations (for example, liposomes), may be utilized.

For transmucosal administration, penetrants appropriate to the barrier to be permeated may be used in the formulation.

Pharmaceutical formulations for parenteral administration, e.g., by bolus injection or continuous infusion, include aqueous solutions of the active compounds in water-soluble form. Additionally, suspensions of the active compounds may be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or other organic oils such as soybean, grapefruit or almond oils, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers or agents that increase the solubility of the compounds to allow for the preparation of highly concentrated solutions. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.

For oral administration, the compounds can be formulated readily by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient to be treated. Pharmaceutical preparations for oral use can be obtained by combining the active compounds with solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate. Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.

Pharmaceutical preparations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers may be added. All formulations for oral administration should be in dosages suitable for such administration.

For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.

For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of, e.g., gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

Further disclosed herein are various pharmaceutical compositions well known in the pharmaceutical art for uses that include intraocular, intranasal, and intraauricular delivery. Suitable penetrants for these uses are generally known in the art. Pharmaceutical compositions for intraocular delivery include aqueous ophthalmic solutions of the active compounds in water-soluble form, such as eyedrops, or in gellan gum (Shedden et al., Clin. Ther., 23(3):440-50 (2001)) or hydrogels (Mayer et al., Opthalmologica, 210(2):101-3 (1996)); ophthalmic ointments; ophthalmic suspensions, such as microparticulates, drug-containing small polymeric particles that are suspended in a liquid carrier medium (Joshi, A., J. Ocul. Pharmacol., 10(1):29-45 (1994)), lipid-soluble formulations (Alm et al., Prog. Clin. Biol. Res., 312:447-58 (1989)), and microspheres (Mordenti, Toxicol. Sci., 52(1):101-6 (1999)); and ocular inserts. All of the above-mentioned references, are incorporated herein by reference in their entireties. Such suitable pharmaceutical formulations are most often and preferably formulated to be sterile, isotonic and buffered for stability and comfort. Pharmaceutical compositions for intranasal delivery may also include drops and sprays often prepared to simulate in many respects nasal secretions to ensure maintenance of normal ciliary action. As disclosed in Remington's Pharmaceutical Sciences, 18th Ed., Mack Publishing Co., Easton, Pa. (1990), which is incorporated herein by reference in its entirety, and well-known to those skilled in the art, suitable formulations are most often and preferably isotonic, slightly buffered to maintain a pH of 5.5 to 6.5, and most often and preferably include antimicrobial preservatives and appropriate drug stabilizers. Pharmaceutical formulations for intraauricular delivery include suspensions and ointments for topical application in the ear. Common solvents for such aural formulations include glycerin and water.

The compounds may also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.

In addition to the formulations described previously, the compounds may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the compounds may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

For hydrophobic compounds, a suitable pharmaceutical carrier may be a cosolvent system comprising benzyl alcohol, a nonpolar surfactant, a water-miscible organic polymer, and an aqueous phase. A common cosolvent system used is the VPD co-solvent system, which is a solution of 3% w/v benzyl alcohol, 8% w/v of the nonpolar surfactant POLYSORBATE 80™, and 65% w/v polyethylene glycol 300, made up to volume in absolute ethanol. Naturally, the proportions of a co-solvent system may be varied considerably without destroying its solubility and toxicity characteristics. Furthermore, the identity of the co-solvent components may be varied: for example, other low-toxicity nonpolar surfactants may be used instead of POLYSORBATE 80™; the fraction size of polyethylene glycol may be varied; other biocompatible polymers may replace polyethylene glycol, e.g., polyvinyl pyrrolidone; and other sugars or polysaccharides may substitute for dextrose.

Alternatively, other delivery systems for hydrophobic pharmaceutical compounds may be employed. Liposomes and emulsions are well known examples of delivery vehicles or carriers for hydrophobic drugs. Certain organic solvents such as dimethylsulfoxide also may be employed, although usually at the cost of greater toxicity. Additionally, the compounds may be delivered using a sustained-release system, such as semipermeable matrices of solid hydrophobic polymers containing the therapeutic agent. Various sustained-release materials have been established and are well known by those skilled in the art. Sustained-release capsules may, depending on their chemical nature, release the compounds for a few weeks up to over 100 days. Depending on the chemical nature and the biological stability of the therapeutic reagent, additional strategies for protein stabilization may be employed.

Additional therapeutic or diagnostic agents may be incorporated into the pharmaceutical compositions. Alternatively or additionally, pharmaceutical compositions may be combined with other compositions that contain other therapeutic or diagnostic agents.

Methods of Administration

The compounds or pharmaceutical compositions may be administered to the patient by any suitable means. Non-limiting examples of methods of administration include, among others, (a) administration though oral pathways, which administration includes administration in capsule, tablet, granule, spray, syrup, or other such forms; (b) administration through non-oral pathways such as rectal, vaginal, intraurethral, intraocular, intranasal, or intraauricular, which administration includes administration as an aqueous suspension, an oily preparation or the like or as a drip, spray, suppository, salve, ointment or the like; (c) administration via injection, subcutaneously, intraperitoneally, intravenously, intramuscularly, intradermally, intraorbitally, intracapsularly, intraspinally, intrasternally, or the like, including infusion pump delivery; (d) administration locally such as by injection directly in the renal or cardiac area, e.g., by depot implantation; as well as (e) administration topically; as deemed appropriate by those of skill in the art for bringing the compound of the invention into contact with living tissue.

Pharmaceutical compositions suitable for administration include compositions where the active ingredients are contained in an amount effective to achieve its intended purpose. The therapeutically effective amount of the compounds disclosed herein required as a dose will depend on the therapeutic moiety incorporated, the route of administration, the type of animal, including human, being treated, and the physical characteristics of the specific animal under consideration. The dose can be tailored to achieve a desired effect, but will depend on such factors as weight, diet, concurrent medication and other factors which those skilled in the medical arts will recognize. More specifically, a therapeutically effective amount means an amount of compound effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated. Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.

As will be readily apparent to one skilled in the art, the useful in vivo dosage to be administered and the particular mode of administration will vary depending upon the age, weight and mammalian species treated, the particular compounds employed, and the specific use for which these compounds are employed. The determination of effective dosage levels, that is the dosage levels necessary to achieve the desired result, can be accomplished by one skilled in the art using routine pharmacological methods. Typically, human clinical applications of products are commenced at lower dosage levels, with dosage level being increased until the desired effect is achieved. Alternatively, acceptable in vitro studies can be used to establish useful doses and routes of administration of the compositions identified by the present methods using established pharmacological methods.

In non-human animal studies, applications of potential products are commenced at higher dosage levels, with dosage being decreased until the desired effect is no longer achieved or adverse side effects disappear. The dosage may range broadly, depending upon the desired affects and the therapeutic indication. Typically, dosages may be between about 10 microgram/kg and 100 mg/kg body weight, preferably between about 100 microgram/kg and 10 mg/kg body weight. Alternatively dosages may be based and calculated upon the surface area of the patient, as understood by those of skill in the art.

The exact formulation, route of administration and dosage for the pharmaceutical compositions of the present invention can be chosen by the individual physician in view of the patient's condition. (See e.g., Fingl et al. 1975, in “The Pharmacological Basis of Therapeutics”, which is hereby incorporated herein by reference in its entirety, with particular reference to Ch. 1, p. 1). Typically, the dose range of the composition administered to the patient can be from about 0.5 to 1000 mg/kg of the patient's body weight. The dosage may be a single one or a series of two or more given in the course of one or more days, as is needed by the patient. In instances where human dosages for compounds have been established for at least some condition, the present invention will use those same dosages, or dosages that are between about 0.1% and 500%, more preferably between about 25% and 250% of the established human dosage. Where no human dosage is established, as will be the case for newly-discovered pharmaceutical compounds, a suitable human dosage can be inferred from ED₅₀ or ID₅₀ values, or other appropriate values derived from in vitro or in vivo studies, as qualified by toxicity studies and efficacy studies in animals.

It should be noted that the attending physician would know how to and when to terminate, interrupt, or adjust administration due to toxicity or organ dysfunctions. Conversely, the attending physician would also know to adjust treatment to higher levels if the clinical response were not adequate (precluding toxicity). The magnitude of an administrated dose in the management of the disorder of interest will vary with the severity of the condition to be treated and to the route of administration. The severity of the condition may, for example, be evaluated, in part, by standard prognostic evaluation methods. Further, the dose and perhaps dose frequency, will also vary according to the age, body weight, and response of the individual patient. A program comparable to that discussed above may be used in veterinary medicine.

Although the exact dosage will be determined on a drug-by-drug basis, in most cases, some generalizations regarding the dosage can be made. The daily dosage regimen for an adult human patient may be, for example, an oral dose of between 0.1 mg and 2000 mg of each active ingredient, preferably between 1 mg and 500 mg, e.g. 5 to 200 mg. In other embodiments, an intravenous, subcutaneous, or intramuscular dose of each active ingredient of between 0.01 mg and 100 mg, preferably between 0.1 mg and 60 mg, e.g. 1 to 40 mg is used. In cases of administration of a pharmaceutically acceptable salt, dosages may be calculated as the free base. In some embodiments, the composition is administered 1 to 4 times per day. Alternatively the compositions of the invention may be administered by continuous intravenous infusion, preferably at a dose of each active ingredient up to 1000 mg per day. As will be understood by those of skill in the art, in certain situations it may be necessary to administer the compounds disclosed herein in amounts that exceed, or even far exceed, the above-stated, preferred dosage range in order to effectively and aggressively treat particularly aggressive diseases or infections. In some embodiments, the compounds will be administered for a period of continuous therapy, for example for a week or more, or for months or years.

Dosage amount and interval may be adjusted individually to provide plasma levels of the active moiety which are sufficient to maintain the modulating effects, or minimal effective concentration (MEC). The MEC will vary for each compound but can be estimated from in vitro data. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. However, HPLC assays or bioassays can be used to determine plasma concentrations.

Dosage intervals can also be determined using MEC value. Compositions should be administered using a regimen which maintains plasma levels above the MEC for 10-90% of the time, preferably between 30-90% and most preferably between 50-90%.

In cases of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration.

The amount of composition administered will, of course, be dependent on the subject being treated, on the subject's weight, the severity of the affliction, the manner of administration and the judgment of the prescribing physician.

Compounds disclosed herein can be evaluated for efficacy and toxicity using known methods. For example, the toxicology of a particular compound, or of a subset of the compounds, sharing certain chemical moieties, may be established by determining in vitro toxicity towards a cell line, such as a mammalian, and preferably human, cell line. The results of such studies are often predictive of toxicity in animals, such as mammals, or more specifically, humans. Alternatively, the toxicity of particular compounds in an animal model, such as mice, rats, rabbits, or monkeys, may be determined using known methods. The efficacy of a particular compound may be established using several recognized methods, such as in vitro methods, animal models, or human clinical trials. Recognized in vitro models exist for nearly every class of condition, including but not limited to cancer, cardiovascular disease, and various immune dysfunction. Similarly, acceptable animal models may be used to establish efficacy of chemicals to treat such conditions. When selecting a model to determine efficacy, the skilled artisan can be guided by the state of the art to choose an appropriate model, dose, and route of administration, and regime. Of course, human clinical trials can also be used to determine the efficacy of a compound in humans.

The compositions may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the active ingredient. The pack may for example comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied with a notice associated with the container in form prescribed by a governmental agency regulating the manufacture, use, or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the drug for human or veterinary administration. Such notice, for example, may be the labeling approved by the U.S. Food and Drug Administration for prescription drugs, or the approved product insert. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition.

EXAMPLES Example 1 Synthesis of 5-methylpyrimidine-2,4,-dione PNA Monomer

An Fmoc protected 5-methylpyrimidine-2,4,-dione peptide nucleic acid monomer was synthesized according to the technique described in Stephen A. Thomson, et al, Tetrahedron Vol. 51, No. 22, pp. 6179-6194, 1995, which is incorporated herein by reference in its entirety. The following synthetic scheme was conducted:

Example 2 Synthesis of PNA Transporter Molecule

A peptide nucleic acid polymer containing guanidinium side groups was synthesized using solid phase techniques on commercially available Rink Amide MBHA resins and Fmoc protected amino acids. An arginine monomer was attached to the resin according to the following scheme:

The PNA monomer from Example 1 was then coupled to the arginine residue by the following reaction:

The above reactions were repeated 8 more times to obtain the following PNA polymer:

Biotin was added as a model terminal group according to the following reaction:

Finally, the polymer was decoupled from the resin by treating with TFA-H₂O-TIS (95:2.5:2.5).

The resulting peptide was purified using a C₁₈ reverse phase HPLC column with CH₃CN/aq. 0.1% TFA gradient elution and the structure was confirmed by mass spectrometry.

Example 3 Transduction Assay

Hela 705 cells were seeded at 1.5×10⁴/well in 96-well plate and cultured overnight (about 60% confluenced). The cells were then rinsed twice with PBS. The compound synthesized in Example 2 was conjugated with streptavidin containing a FITC florescent dye. 100 μM of the produce in PBS (pH: 7.4) was applied to the cell cultures and the cultures were incubated for 30 min at 37° C. The test compound solution was then removed and the cells were rinsed twice with PBS. The cells were fixed by treatment with 0.2% Glutaraldehyde in PBS for 5 min at room temperature. The cells were again rinsed twice with PBS and then incubated with 10% methanol in PBS for 10 min at room temperatures. The cells were then rinsed twice with PBS and incubated with 10% FBS in DMEM for 30 min at 37° C. Next, the cells were rinsed once with PBS and incubated with SA-FITC (1:100 diluted in PBS) for 30 min at 37° C. Finally, the cells were again rinsed twice with PBS and observed under a fluorescence microscope.

FIG. 1 depicts fluorescence micrographs of cells exposed to the oligomer test compound and cells only exposed to PBS. The micrographs illustrate that the test compound was taken up into the cells.

Example 4 Transdermal Crossing

Female nude mice (NU/NU) were injected with anesthesia (Ketaset 25 mg/mL, Xylazine 5 mg/mL, 50 μL/mouse). 130 λL of the compound from Example 2 in PBS was then applied to the skin of the mice. After 1 hour of treatment, skin samples were taken and frozen with OCT compound immediately by liquid nitrogen. The frozen samples were sliced to 5 μm thickness and placed on glass slides.

The frozen tissue slides were dried at room temperature and fixed in acetone for 10 minutes. The samples were then rinsed in PBS twice for 10 min each with gentle shaking at 40-50 RPM. The samples were pre-incubated with a blocking reagent (0.2% gelatin in PBS) for 30 min at room temperature. The samples were then incubated with optimal diluted substrate for 1 hr at room temperature (Streptavidin-FITC, 1:100 diluted in PBS). After rinsing in PBS for 10 min with gentle shaking at 40-50 RPM, the samples were soaked in hematoxylin for 2 min. Finally, the samples were again rinsed in PBS for 10 min with gentle shaking at 40-50 RPM and extra PBS was sucked out. The samples were mounted with DAKO anti-fading mounting medium and observed under a fluorescence microscope. The biotinylated test compound was visualized by binding with the streptavidin conjugated with FITC.

FIG. 2 depicts the fluorescence micrographs of tissue samples exposed to the test compound and control samples exposed only to PBS. The micrographs illustrate that the test compound was taken up into the tissue samples. 

1. A compound having the formula:

wherein: each L is a bond; each T is a terminal group separately selected from the group consisting of hydrogen, an amine group, and a reporting moiety; each R is independently selected from the group consisting of optionally substituted pyrimidine, optionally substituted purine, and

wherein said pyrimidine and purine are optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈ alkyl; each G is separately selected to be a guanidinium group having the formula:

each R¹, R², R³, and R⁴ are independently hydrogen or C₁-C₁₂ alkyl; each n, and p are independently integers in the range from 1 to 6; m, and q are 0; and r is an integer selected from 4 to
 10. 2. The compound of claim 1, having the formula:

wherein n and p are
 1. 3. The compound of claim 1, wherein R¹, R², R³, and R⁴ are hydrogen.
 4. The compound of claim 1, wherein at least one T is


5. The compound of claim 1, wherein each R is independently selected from the group consisting of an optionally substituted pyrimidine and an optionally substituted purine.
 6. The compound of claim 5, wherein each R is independently selected from the group consisting of uracil, thymine, cytosine, adenine, and guanine, said uracil, thymine, cytosine, adenine, and guanine optionally linked to the compound via a linker comprising an optionally substituted C₁-C₈alkyl.
 7. The compound of claim 5, wherein at least one R has the formula:


8. The compound of claim 1, wherein at least one R has the formula:


9. The compound of claim 3, wherein each G is:


10. The compound of claim 1, having the structure;


11. A compound having the formula:

L is a bond; and T is a terminal group separately selected fron the group consisting of hydrogen, an amine group and a reporting moiety.
 12. A method for transporting a compound of claim 1 across a biological membrane, comprising contacting a biological membrane with the compound of claim
 1. 13. The method of claim 12, wherein said biological membrane is a cancer cell membrane.
 14. A pharmaceutical composition, comprising a compound of claim 1, and a pharmaceutically acceptable carrier, diluent, or excipient.
 15. The compound having the structure: 